JPH0669783U - Freezing temperature measuring probe for molten metal - Google Patents

Abstract

(57) [Summary] [Purpose] The location of the nest that occurs in the sample is separated from the thermocouple, and the solidification temperature is measured accurately. [Structure] From the bottom of the sampling container 1 to the solidification temperature sensor 2
In the probe for measuring the solidification temperature for molten metal, in which the thermocouple 3 of FIG.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a probe used for estimating the carbon content by measuring the solidification temperature of a collected molten metal.

[0002]

[Prior art]

 Conventionally, in a converter, which has been the center of the steelmaking process of steel, the temperature, solidification temperature, oxygen content, etc. are measured using a sublance with a consumable probe as disclosed in Japanese Patent Publication No. The end point is controlled by the dynamic control system, and the end temperature and components are checked. All of these measurements require swiftness and certainty of accuracy, and in recent years, higher accuracy is required.

Under such circumstances, the conventional sublance probe having the structure shown in FIG. 3 has been used. In the figure, 1 is a sample collection container, 5 is a temperature / acid measurement sensor, 6 is a protective tube, 7 is an inlet hole cover, 8 is a sample introduction part, and the sample collection container 1 is screwed from the top. A deoxidizing Al member 4 is arranged, and a thermocouple 3 which is a detecting portion of the solidification temperature sensor 2 projects from the center of the bottom of the Al member 4. When such a probe is immersed in molten steel, the inlet hole lid 7 is melted and molten steel as a sample flows into the sampling container 1 through the sample introduction part 8 and is solidified there. The temperature is measured by the solidification temperature sensor 2 to determine the carbon content of the molten steel. The deoxidizing Al member 4 is arranged in the sample collection container 1 so that a sound sample having no bubbles, that is, no cavities during solidification can be obtained.

[0004]

[Problems to be solved by the device]

 However, with conventional probes, it is actually difficult to always obtain a healthy sample without nests, and nests often occur. That is, FIG. 4 is a cross-sectional view of the sample 10 taken by the probe of FIG. 3, but as shown in the figure, the sample 9 had a nest 9 in the finally solidified central portion.

On the other hand, as described above, the thermocouple 3 is arranged in the central portion of the lower portion of the sampling container 1 so as to project from the bottom portion, and the nest 9 is located around the thermocouple 3. Therefore, the conventional probe has a problem that a space around the contact portion of the thermocouple 3 becomes a space and is in a non-contact state, and the solidification temperature sensor 2 cannot accurately measure the solidification temperature. In addition, carbon segregation may occur in the final solidification part, and there is a problem in the representativeness of the solidification temperature measured in the sample in which the cavities are left. As a result, the accuracy of carbon estimation deteriorates, which adversely affects the end point control by dynamic control. That is, there was a problem such as deviation from the target carbon amount at the end point.

The present invention was devised in view of the above problems of the prior art, and is a solidification temperature measuring probe for molten metal capable of measuring the solidification temperature with high accuracy and improving the accuracy of carbon content estimation. Is to provide.

[0007]

[Means for solving problems]

 As shown in Fig. 4, in the conventional probe, a cavity 9 was formed in the approximate center of the sample collection container 1, but this was completed in the central part as the cooling for solidifying the molten steel sample progressed from the surroundings. This is because

Therefore, if the position of the final solidification of the molten steel sample is shifted from the central portion, the position of the nest 9 that occurs is also displaced, and the periphery of the thermocouple 3 contact located in the central portion of the sampling container 1 is displaced. The above problem due to the space around the thermocouple 3 can be solved.

Based on the above findings, the inventors of the present invention have studied the structure of a probe that shifts the final solidification position of a molten steel sample from the center of the sampling container 1, and devised the present invention. Came to.

That is, the solidification temperature measurement probe for molten metal according to the present invention is a solidification temperature measurement probe for molten metal in which the thermocouple of the solidification temperature sensor projects from the bottom of the sampling container. The basic feature is that the components near the thermocouple are made of a member having a higher cooling capacity than the upper side thereof.

[0011]

[Action]

 In the present invention, since the components near the thermocouple in the sampling container are made of a member having a higher cooling capacity than the upper side thereof, the cooling rate at the vicinity of the thermocouple of the molten steel sample and at the upper side thereof. Will change, and solidification will start near the thermocouple, and finally solidification will be completed on the upper side. In other words, the final solidified portion of the sample will move to a position higher than that of the conventional probe, and it is possible to effectively prevent the generation of cavities and segregation near the thermocouple contact.

[0012]

【Example】

 A specific embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments.

FIG. 1 shows an embodiment of the probe according to the present invention, and its basic structure is the same as that of the conventional probe shown in FIG. That is, 1 is a sample collection container, 5 is a temperature measurement / acid measurement sensor, 6 is a protective tube, 7 is an inlet hole cover, 8 is a sample introduction part, and the sample collection container 1 has a spiral shape from the top. A deoxidizing Al member 4 is arranged, and a thermocouple 3 which is a detecting portion of the solidification temperature sensor 2 projects from the bottom center side thereof.

The characteristic part of this embodiment is included in the constituent members of the sample collection container 1. That is, from the bottom of the sample collection container 1 to the vicinity 1a of the tip of the thermocouple 3 is formed by a metal having a large cooling capacity, and the upper portion 1b is formed by molding sand having a relatively small cooling capacity.

When the probe of the present embodiment as described above is immersed in molten steel, the probe 7 of the inlet hole is melted when the probe is immersed in molten steel, and the molten steel to be a sample passes through the sample introduction portion 8 to sample. After flowing into the container 1 and solidified therein, the temperature is measured by the solidification temperature sensor 2, the carbon content of the molten steel is obtained, and the composition is analyzed.

Here, since the sampling container 1 is made of metal from the bottom to the vicinity 1a of the tip of the thermocouple 3 and its upper portion 1b is made of foundry sand, the final solidified portion of the sample is the upper portion having a smaller cooling capacity. It is the side that contacts 1b. FIG. 2 is a cross-sectional view of the sample 10 taken by the probe of FIG. 1, but the nest 9 generated as shown is on the upper side of the sample 10 and separated from the position of the thermocouple 3.

Therefore, in this embodiment, the thermocouple 3 can be brought into contact with a sample that is completely free of segregation, so that the solidification temperature can be accurately measured and the carbon content can be accurately estimated. .

Further, when the carbon amount was actually estimated using the probe of this example, the accuracy was improved from 0.020% to 0.007% in the conventional σn-1.

In the present embodiment, foundry sand and metal were used as the constituent members of the sample collection container 1, but the present invention is not limited to this, and the thermocouple 3 near the tip 1a is compared with the upper part 1b. Any member may be used as long as it has a large cooling capacity.

[0020]

[Effect of device]

 As described above, according to the solidification temperature measuring probe for molten metal of the present invention, the position of the nest generated in the solidification sample can be separated from the vicinity of the thermocouple, and the thermocouple is a sample without complete segregation. Since they can come into contact with each other, the solidification temperature can be accurately measured, and thus the carbon content can be accurately estimated.

[Brief description of drawings]

FIG. 1 is a sectional view of a probe showing an embodiment of the present invention.

2 is a cross-sectional view of a sample taken with the probe of FIG.

FIG. 3 is a cross-sectional view of a conventional probe.

4 is a cross-sectional view of a sample taken with the probe of FIG.

[Explanation of symbols]

 1 Sampling container 2 Freezing temperature sensor 3 Thermocouple 4 Al member for deoxidation 5 Temperature / acid sensor 6 Protective tube 7 Inlet hole cover 8 Sample introduction part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuya Kimura 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Eisaku Wada 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Main Steel Pipe Co., Ltd. (72) Inventor Shigeru Inoue 1-2, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Inventor Shigeomi Sato 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe (72) Inventor Takahiro Yoshikawa 5-2-10-105 Motonakayama, Funabashi City, Chiba Prefecture (72) Koji Onda 2-2-16-503 Higashi Nakayama, Funabashi City, Chiba Prefecture

Claims (2)

[Scope of utility model registration request] 1. A solidification temperature measuring probe for molten metal, wherein a thermocouple of a solidification temperature sensor projects from the bottom of a sampling container, wherein a component near the thermocouple in the sampling container is cooled from the upper side thereof. A molten metal solidification temperature measuring probe, characterized in that it is composed of a member having a large diameter. 2. The solidification temperature measuring probe for molten metal according to claim 1, wherein a metal is used as a constituent member near the thermocouple and a molding sand is used as a constituent member on an upper side thereof in the sampling container. A solidification temperature measuring probe for molten metal according to claim 1.